1. Field of the Invention
The present invention relates to a film image input method and more particularly to a film image input method used for a film scanner which reads out a frame image of developed photographic film by means of a line sensor and processes an image signal in accordance with the picked-up frame image and the method is able to prevent the film from being discolored and prevent a capstan from being deformed.
2. Description of the Related Art
The Japanese Patent Application Laid-open No. 2-276362, the Japanese Patent Application Laid-open No. 4-311940, and the Japanese Utility Model Application Laid-open No. 4-4456 disclose a film image input method which comprises the steps of illuminating by means of a light source a long developed photographic film which is being transported, picking up a illuminated frame image of the film by means of a line sensor such as a CCD, etc., converting the image into an image signal, and applying the image signal to a TV monitor so as to display a frame image.
In one of the conventional film image input methods, an infrared cut filter is provided between a light source and photographic film to cut a heat ray in an infrared area of the illumination light in order to prevent the frame image of the film from being discolored which is caused by the illumination light.
However, in the conventional film image input method, after one frame image is picked up by the line sensor, a film transport is temporarily stops until the pickup for next frame image is started. Therefore, if the operation has not been executed for a long time, the rear end portion of the picked up frame is illuminated by the illumination light for a long time. As a result, there is a problem in that the image on the rear end portion of the frame is discolored by a visible light and the infrared radiation.
Further, the conventional film image input apparatus has a mechanism which transports the film with a pinch roller and a capstan, and the roller for driving the film is normally made of a material such as rubber, etc. Therefore, there is a problem in that the roller tends to be deformed if the capstan is pressed against the pinch roller for a long time.